Boiler for arranging recirculation flue by utilizing spare space

Abstract

The invention provides a boiler for arranging a recirculation flue by utilizing a spare space, and belongs to the technical field of boiler manufacturing and transformation. The problems that a nozzle tube panel is difficult to design, a hanging bracket is difficult to arrange, interference with peripheral equipment is prone to occurring and the like due to the fact that a recirculation smoke nozzle is arranged at the top or the bottom of a combustor set, the height of the combustor set is further increased, and the overall height of the boiler is increased are solved. A direct-current burner set is arranged in the boiler and comprises a standby secondary air compartment, a standby burner and a secondary air and recirculating flue gas double-switching air chamber assembly, the standby burner is located at the top end of the direct-current burner set, the standby secondary air compartment is located below the standby burner, and the secondary air and recirculating flue gas double-switching air chamber assembly is located below the standby burner. And the secondary air and recirculating flue gas double-switching air chamber assembly is arranged in the standby secondary air compartment. The boiler is mainly used for boiler structure optimization design, and the space in the boiler is effectively utilized.

Description

Technical Field

[0001] The invention belongs to the technical field of boiler manufacturing and modification, and in particular relates to a boiler using spare space to arrange a recirculation flue. Background Art

[0002] Boiler internal corner tangential circular direct current pulverized coal burner groups are usually arranged at the corners of the boiler or the water-cooled wall. The conventional distribution method is 4 corners, 6 corners and 8 corners. Depending on the type and capacity of the boiler, the height of the single-angle burner group can be designed to be 5 to 20 meters, occupying a large amount of space in the furnace and outside the furnace. The reheat steam temperature of the secondary reheat boiler is regulated by flue gas recirculation technology. The flue gas is sent into the furnace from the recirculating flue gas nozzle set at the top or bottom of the burner. The setting of the recirculating flue gas nozzle further increases the height of the burner group, which increases the overall height of the boiler, resulting in difficulties in the design of the nozzle tube screen, the difficulty in arranging the hanger, and easy interference with surrounding equipment. At the same time, it increases the overall cost of the boiler. Summary of the invention

[0003] In view of this, in order to solve the problem that the recirculating flue gas nozzle is set at the top or bottom of the burner group of the boiler, the height of the burner group is further increased, which increases the overall height of the boiler, resulting in problems such as difficulty in nozzle tube panel design, difficulty in hanger arrangement, and easy interference with surrounding equipment. The present invention proposes a recirculating flue boiler that utilizes spare space to arrange the recirculating flue gas nozzle and the nozzle body in the spare secondary air compartment below the spare burner at the top of the boiler burner group. The introduction position of the recirculating flue gas is crucial to the boiler recirculating flue gas process. The setting position of the recirculating flue gas nozzle of the present invention effectively utilizes the space in the spare secondary air compartment, and the flue gas introduction position can meet the process requirements of the boiler flue gas recirculation working process. Under the premise of not affecting the function of the spare secondary air compartment, the arrangement of the recirculating flue gas nozzle is completed, and the impact on the normal combustion process of the boiler is small, the overall height of the boiler burner group is reduced, and the overall cost of the boiler is reduced. At the same time, a guide plate is arranged inside the recirculating flue gas nozzle body to enhance the stability of the airflow. In order to enable some structures to adapt to two different working conditions of secondary air supply and recirculating flue gas supply, wear-resistant design is adopted for components such as nozzles, guide plates and pipes.

[0004] To achieve the above object, the present invention adopts the following technical scheme: a recirculation flue boiler is arranged using a spare space, a direct current burner group is arranged inside the boiler, the direct current burner group includes a spare secondary air compartment, a spare burner and a secondary air and recirculation flue gas double switch air chamber assembly, the spare burner is located at the top of the direct current burner group, the spare secondary air compartment is located below the spare burner, and the secondary air and recirculation flue gas double switch air chamber assembly is arranged in the spare secondary air compartment;

[0005] The secondary air and recirculated flue gas dual switchable air chamber assembly comprises a nozzle, a nozzle body, a recirculated flue gas duct and a secondary air introduction duct, wherein one end of the nozzle body is connected to the nozzle, and the other end is respectively connected to the recirculated flue gas duct and the secondary air introduction duct.

[0006] Furthermore, a first gate valve is provided on the recirculating flue gas duct, and a second gate valve is provided on the secondary air introduction duct.

[0007] Furthermore, a fixed guide plate and a rotating guide plate are provided inside the nozzle body. The fixed guide plate is arranged along the center line of the nozzle body and is vertically fixed at the center of the nozzle body. The rotating guide plate is hinged to the side of the fixed guide plate away from the nozzle and can rotate around the side.

[0008] Furthermore, the rotating guide plate also includes a driving device, and the driving device is fixedly connected to the rotating guide plate.

[0009] Furthermore, the driving device is a crank-pull rod structure, which includes a first crank, a pull rod, a second crank and a driving rod. One end of the first crank is fixed to the rotating guide plate, and the other end is hinged to the pull rod; one end of the second crank is hinged to the pull rod, and the other end is fixed to the driving rod. The first crank and the second crank are arranged parallel to each other; the driving rod is installed on the recycled flue gas duct.

[0010] Furthermore, the first gate valve, the second gate valve and the driving device are all driven manually, pneumatically or electrically.

[0011] Furthermore, the windward surfaces of the first gate valve, the second gate valve, the fixed guide plate and the rotating guide plate are all lined with silicon carbide or alumina ceramic material.

[0012] Furthermore, the nozzle is made of wear-resistant and heat-resistant cast steel, and the nozzle body and the recirculating flue gas duct are made of carbon steel, lined with silicon carbide or alumina ceramics.

[0013] Compared with the prior art, the beneficial effects of the recirculation flue boiler arranged using spare space in the present invention are:

[0014] 1. The present invention sets the recirculating flue gas nozzle and the nozzle body in the spare secondary air compartment of the boiler, which effectively utilizes the limited space in the boiler burner area without affecting the function of the secondary air compartment and the normal operation of the boiler, reduces the height of the burner group and the overall height of the boiler, and reduces the overall cost of the boiler.

[0015] 2. The present invention sets the recirculating flue gas nozzle and the nozzle body in the spare secondary air compartment between the spare burner at the top of the boiler burner group and the first burner. Setting the recirculating flue gas nozzle at this position meets the process requirements of the boiler flue gas recirculation working process, and completes the arrangement of the recirculating flue gas nozzle without affecting the function of the spare secondary air compartment.

[0016] 3. The present invention arranges a guide plate inside the recirculating flue gas nozzle body, thereby improving the stability of the secondary air flow and the recirculating flue gas flow.

[0017] 4. The present invention takes into account the scouring of fly ash in the recycled flue gas and selects materials for some components to prevent wear, thereby increasing the service life of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0019] Figure 1 It is a front view of the position and structure of the spare burner and spare secondary air compartment at the top of the direct current burner group of the present invention;

[0020] Figure 2 A top view of the spare secondary air compartment of the present invention;

[0021] Figure 3 This is a front view of the secondary air and recirculated flue gas dual switchable air chamber assembly of the present invention arranged in the spare secondary air compartment;

[0022] Figure 4 A top view of the secondary air and recirculated flue gas dual switchable air chamber assembly of the present invention arranged in the spare secondary air compartment;

[0023] Figure 5 A front view of a nozzle body of the present invention in which a fixed guide plate, a rotating guide plate and a driving device are arranged;

[0024] Figure 6 A top view of a nozzle body of the present invention in which a fixed guide plate, a rotating guide plate and a driving device are arranged;

[0025] Figure 7 A top view of the main structure of the present invention when conveying recirculated flue gas;

[0026] Figure 8 A top view of the main structure of the present invention when conveying secondary air;

[0027] In the figure: A-spare secondary air compartment; B-spare burner; C-first burner

[0028] 1-nozzle; 2-nozzle body; 3-recirculating flue gas duct; 4-secondary air introduction duct; 5-first gate valve; 6-second gate valve;

[0029] 21 - fixed guide plate; 22 - rotating guide plate; 23 - first crank; 24 - pull rod; 25 - second crank; 26 - driving rod. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely explain the technical solutions in the embodiments of the present invention. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict, and the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0031] 1. Specific implementation method 1, see Figure 1-8 To explain the present embodiment, a recirculating flue boiler is arranged using a spare space, and a DC burner group is arranged inside the boiler. The DC burner group includes a spare secondary air compartment A, a spare burner B, and a secondary air and recirculating flue gas dual-switchable air chamber assembly. The spare burner B is located at the top of the DC burner group, and the spare secondary air compartment A is located below the spare burner B. The secondary air and recirculating flue gas dual-switchable air chamber assembly is arranged in the spare secondary air compartment A. When the boiler is operating normally, the spare secondary air compartment A is idle, so it is considered to set the recirculating flue gas duct therein for the introduction of recirculating flue gas. When there is an emergency, by closing the recirculating flue gas duct 3, the nozzle body 2 is connected to the secondary air introduction duct 4, and secondary air is supplied to the boiler, so as to realize the basic function of the spare secondary air compartment A.

[0032] The secondary air and recirculated flue gas dual-switchable wind chamber assembly includes a nozzle 1, a nozzle body 2, a recirculated flue gas duct 3 and a secondary air introduction duct 4, wherein one end of the nozzle body 2 is connected to the nozzle 1, and the other end is respectively connected to the recirculated flue gas duct 3 and the secondary air introduction duct 4. The introduction position of the recirculated flue gas is crucial to the boiler recirculation flue gas process, directly affecting the boiler efficiency, combustion stability and emission control. The present invention is arranged between the two layers of pulverized coal burners at the top of the boiler burner group, in the spare secondary air compartment A between the topmost spare pulverized coal burner B and the conventionally used first burner C below it, and the recirculated flue gas is introduced from the upper part of the furnace, which can effectively dilute the flue gas, reduce the exhaust temperature, and improve the boiler efficiency. Compared with the introduction from the combustion zone, the upper introduction has less interference with the combustion process, which is conducive to maintaining the stability of boiler combustion.

[0033] The recirculating flue gas duct 3 of the present application is provided with a first gate valve 5, and the secondary air introduction duct 4 is provided with a second gate valve 6. The pipeline valves of the present invention all use gate valves, which adopt a flat sealing design, can effectively prevent gas leakage when closed, and are suitable for high pressure and high temperature environments.

[0034] The nozzle body 2 of the present application is provided with a fixed guide plate 21 and a rotating guide plate 22, wherein the fixed guide plate 21 is arranged along the center line direction of the nozzle body 2 and is vertically fixed in the center of the nozzle body 2, and the rotating guide plate 22 is hinged to the side of the fixed guide plate 21 away from the nozzle 3 and can rotate around the side. The recirculation nozzle body of the present invention is provided with a fixed guide plate and a rotating guide plate to adjust the airflow balance on the left and right sides of the nozzle.

[0035] The rotating guide plate 22 described in the present application further includes a driving device, and the driving device is fixedly connected to the rotating guide plate 22 .

[0036] The driving device described in the present application is a crank pull rod structure, which includes a first crank 23, a pull rod 24, a second crank 25 and a driving rod 26. One end of the first crank 23 is fixed to the rotating guide plate 22, and the other end is hinged to the pull rod 24; one end of the second crank 25 is hinged to the pull rod 24, and the other end is fixed to the driving rod 26. The first crank 23 and the second crank 25 are arranged parallel to each other; the driving rod 26 is installed on the recirculating flue gas duct 3. The crank pull rod uses the principle of lever, and can realize the opening and closing of the valve plate with a small operating force, which is suitable for manual operation. And it has a simple structure, few parts, low failure rate, easy maintenance, and is suitable for long-term use. The crank pull rod structure has strong applicability and can work stably even in high-temperature and high-pressure pipelines for conveying flue gas.

[0037] The first gate valve 5, the second gate valve 6 and the driving device of the present application are all driven manually, pneumatically or electrically. The present invention can select a suitable driving mode according to different working conditions. For small systems, manual driving can be selected from the perspective of structure and cost; starting driving can be selected from the perspective of response speed and operating frequency; and electric driving can be selected from the perspective of improving the degree of automation of the equipment, realizing remote control and precise adjustment.

[0038] In the present application, the windward surfaces of the first gate valve 5, the second gate valve 6, the fixed guide plate 21 and the rotating guide plate 22 are all lined with silicon carbide or alumina ceramic material.

[0039] The nozzle 1 described in the present application is made of wear-resistant and heat-resistant cast steel, and the nozzle body 2 and the recirculating flue gas duct 3 are made of carbon steel, lined with silicon carbide or alumina ceramics.

[0040] The present invention takes into account that the recycled flue gas contains a large amount of fly ash, so all equipment is designed to be wear-resistant. Wear-resistant and heat-resistant cast steel can maintain stable performance in a high temperature environment, which is suitable for the working environment of the present invention. It has high hardness and can resist the scouring and wear of fuel particles, thereby extending the life of the nozzle. Silicon carbide and alumina ceramic surfaces have the advantages of high hardness, high temperature resistance and corrosion resistance, and are suitable for use in the high temperature environment of the recycled flue gas process.

[0041] The present invention has two working modes. When conveying recirculated flue gas, the first gate valve 5 is opened, the second gate valve 6 is closed, and the rotating guide plate 22 is rotated to a position on the same plane as the fixed guide plate 21 by the driving mechanism to stabilize the recirculated flue gas flow and supply the recirculated flue gas to the boiler. When an emergency occurs in the boiler and the spare secondary air duct needs to be used, the first gate valve 5 is closed, the second gate valve 6 is opened, and the rotating guide plate 22 is rotated to the center line direction of the secondary air introduction duct 4 by the driving mechanism to stabilize the secondary air flow and supply the secondary air to the boiler.

[0042] The embodiments of the present invention disclosed above are only used to help illustrate the present invention. The embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. According to the content of this specification, many modifications and changes can be made. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well.

Claims

1. A recirculation flue boiler using spare space, characterized in that: A direct current burner group is arranged inside the boiler, and the direct current burner group comprises a spare secondary air compartment (A), a spare burner (B) and a secondary air and recirculating flue gas double switching air chamber assembly, wherein the spare burner (B) is located at the top of the direct current burner group, the spare secondary air compartment (A) is located below the spare burner (B), and the secondary air and recirculating flue gas double switching air chamber assembly is arranged in the spare secondary air compartment (A); The secondary air and recirculated flue gas dual switchable air chamber assembly comprises a nozzle (1), a nozzle body (2), a recirculated flue gas duct (3) and a secondary air introduction duct (4); one end of the nozzle body (2) is connected to the nozzle (1), and the other end is respectively connected to the recirculated flue gas duct (3) and the secondary air introduction duct (4).

2. The method of arranging a recirculation flue boiler using spare space according to claim 1, characterized in that: The recirculating flue gas duct (3) is provided with a first gate valve (5), and the secondary air introduction duct (4) is provided with a second gate valve (6).

3. The method of arranging a recirculating flue boiler using spare space according to claim 2, characterized in that: A fixed guide plate (21) and a rotating guide plate (22) are provided inside the nozzle body (2); the fixed guide plate (21) is arranged along the center line direction of the nozzle body (2) and is vertically fixed at the center of the nozzle body (2); the rotating guide plate (22) is hinged to the side of the fixed guide plate (21) away from the nozzle (3) and can rotate around the side.

4. The method of arranging a recirculating flue boiler using spare space according to claim 3, characterized in that: The rotating guide plate (22) further comprises a driving device, which is fixedly connected to the rotating guide plate (22).

5. The method of arranging a recirculating flue boiler using spare space according to claim 4, characterized in that: The driving device is a crank-pull rod structure, which includes a first crank (23), a pull rod (24), a second crank (25) and a driving rod (26). One end of the first crank (23) is fixed to the rotating guide plate (22), and the other end is hinged to the pull rod (24); one end of the second crank (25) is hinged to the pull rod (24), and the other end is fixed to the driving rod (26). The first crank (23) and the second crank (25) are arranged parallel to each other; the driving rod (26) is installed on the recirculating flue gas duct (3).

6. The method of arranging a recirculating flue boiler using spare space according to claim 4, characterized in that: The first gate valve (5), the second gate valve (6) and the driving device are all driven manually, pneumatically or electrically.

7. The method of arranging a recirculating flue boiler using spare space according to claim 4, characterized in that: The windward surfaces of the first gate valve (5), the second gate valve (6), the fixed guide plate (21) and the rotating guide plate (22) are all lined with silicon carbide or alumina ceramic material.

8. A recirculation flue boiler using spare space according to any one of claims 1 to 6, characterized in that: The nozzle (1) is made of wear-resistant and heat-resistant cast steel, and the nozzle body (2) and the recirculating flue gas duct (3) are made of carbon steel, which is lined with silicon carbide or alumina ceramics.

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